Dumb JAMMA question

grandmascrack

Krauser's Shoe Shiner
Joined
Feb 8, 2003
Posts
243
Please excuse my ignorance, but I'm a noob at best when it comes to voltage/wiring/etc, but I'm working on an idea I have and I'm trying to figure out how to trip the COIN pin on a JAMMA board to add a token to the machine.

I've wired a JAMMA fingerboard to act as a middleman between the cabinet and the arcade board and have wired an extra wire to pin 16 that goes to a pin on an Arduino board. I then use the Arduino to send send a signal and trip the pin to add a token.

In theory, this makes sense in my head, but so far it's not working and my first thought is that maybe I don't have the right/enough voltage to trip the pin on the JAMMA harness, or if an Arduino can do it at all?

Thoughts?
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
All I/O signals are active low, you need to ground the signal not pull up.

You could also just put the JAMMA board in free play mode or wire the coin button to an unused button on the CP or add a small push button somewhere. There's also a product called easycoinup I think that is a flat button that looks like a quarter that you can put almost anywhere on the cab.
 

grandmascrack

Krauser's Shoe Shiner
Joined
Feb 8, 2003
Posts
243
Ah, ok, I think I might be using the wrong terminology.

So on the Arduino board, I have the wire connected to pin 16 on the JAMMA adapter in pin 6. In the code, pin 6 is set to Output and High, initially. The Arduino board is hooked up to an RFID antenna and, when a certain card is read, pin 6 is set to Low to interrupt the signal for a token to be credit.

Apologies, hope the above makes a little more sense in response to your comment?

Thanks for the help!

::edit::

Oh wait, I think I get it. I'm not sending anything so once the voltage on that pin(?) is grounded, then it credits the machine. The wire I added isn't necessarily grounding the signal since the voltage can just bypass the wire going to the arduino and instead continue over the original connection made on the 1:1 adapter.
 
Last edited:

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
Ah, ok, I think I might be using the wrong terminology.

So on the Arduino board, I have the wire connected to pin 16 on the JAMMA adapter in pin 6. In the code, pin 6 is set to Output and High, initially. The Arduino board is hooked up to an RFID antenna and, when a certain card is read, pin 6 is set to Low to interrupt the signal for a token to be credit.

Apologies, hope the above makes a little more sense in response to your comment?

Thanks for the help!

Make sure you have a ground tied from the Arduino to the JAMMA board. Both need to reference ground as 0.
 

DNSDies

I LOVE HILLARY CLINTON!
Joined
Mar 15, 2015
Posts
1,983
Correct me if I'm wrong
Shouldn't the coin button not have any signal at all going into it, then be grounded for when a coin is inserted?

Your arduino should be acting like a momentary switch, not sending any signal to Jamma Pin 16.
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
Correct me if I'm wrong
Shouldn't the coin button not have any signal at all going into it, then be grounded for when a coin is inserted?

Your arduino should be acting like a momentary switch, not sending any signal to Jamma Pin 16.

Correct, he shouldn't be pulling it up since it's already being pulled up. It just needs to ground the pin when triggered.
 

grandmascrack

Krauser's Shoe Shiner
Joined
Feb 8, 2003
Posts
243
Yeah, I think it just clicked in my head. I believe I need to wire up a wire to the adapter that goes from ground on the JAMMA adapter to a ground pin on the Arduino...?
 

BLEAGH

Haomaru's Blade Shiner
Joined
Mar 24, 2007
Posts
679
Why are you messing with an arduino?

Just hook up a pushbutton.
 

bustedstr8

Trollbox Trade Federation,
Joined
Oct 15, 2007
Posts
943
You need to use a buffer with open collector outputs like a 7407 since all the signals will have pullups like James said.
 

grandmascrack

Krauser's Shoe Shiner
Joined
Feb 8, 2003
Posts
243
So I soldered a wire to Pin 1 on the JAMMA adapter and inserted it into one of the grounds on the arduino. I also realized I actually had the other soldered wire on Pin 15 instead of 16 on the adapter. That said, it worked! It triggered the test menu successfully.

I took the adapter back to my soldering station, soldered the wire to pin 16 instead of 15, tried it again, and got zilch. I'm a bit more lost now. Why did it work for the test menu on pin 15 and not when it's wired up to pin 16?
 

DNSDies

I LOVE HILLARY CLINTON!
Joined
Mar 15, 2015
Posts
1,983
Why are you messing with an arduino?

Just hook up a pushbutton.

I believe he's trying to do a NFC card reader that triggers the coin press.
Something like an arcade money card?
 

MikanBox

n00b
Joined
Oct 15, 2016
Posts
13
when in doubt. Use 5v relay. :snack:
(it'll pretty much act like a switch, And you get an audible click when it activates. win win)
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
when in doubt. Use 5v relay. :snack:
(it'll pretty much act like a switch, And you get an audible click when it activates. win win)

Only way that would work is if you paired the relay with a hex inverter. So when the relay activates and provides 5v the inverter will instead ground the line.
 

MikanBox

n00b
Joined
Oct 15, 2016
Posts
13
Only way that would work is if you paired the relay with a hex inverter. So when the relay activates and provides 5v the inverter will instead ground the line.

you sure about that? :vik:
the magnetic part is attached to the arduino board
(hence the 5v part. to activate the electro-magnet)

And the rest of the relay just acts like a normal switch. (its not a transistor xD)

3051_1_Relay_Diagram.jpg

edit. got it working. :cool: (ignore shitty test bench)

 
Last edited:

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
you sure about that? :vik:
the magnetic part is attached to the arduino board
(hence the 5v part. to activate the electro-magnet)

And the rest of the relay just acts like a normal switch. (its not a transistor xD)

View attachment 39954

I know how relays work, if that's the question. His problem isn't so much about a switch, it's trying to trigger it to ground the signal to activate it.
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
Also it depends on his design as well. He can implement the relay but it depends on the relay itself.
 

MikanBox

n00b
Joined
Oct 15, 2016
Posts
13
I think your wording confused me. When you say 5v relay it means it's spitting out 5v when active. You don't really include the power requirement when describing a relay.
sorry bout that :/

I just worded it so I'd be easy to google. (googles suggestion would usually suggest "5v relay arduino" as you type it out.
 
Top